You can do the following:
1. In the OBi, set:
System Management -> Device Admin -> Web Server -> Port : 8080
System Management -> Device Admin -> Web Server -> AdminPassword : (something secret)
2. In your router, forward port 8080 to the OBi's LAN IP address.
Then you can log into your OBi from anywhere using:
http://ipaddress:8080where IPAddress is the OBi's LAN IP address if logging in locally or your public (ISP assigned) IP address if logging in remotely.
Then you can not only reboot the OBi remotely, you can totally administer it remotely.
If your public IP address changes frequently, you'll probably need to set up a
DynDNS account that will give you a hostname that always has your current IP address which can then be used remotely:
http://hostname.dyndns.org:8080